Risk Factors for Postoperative Knee Stiffness in Patients with Anteromedial Knee Osteoarthritis Undergoing Unicompartmental Knee Arthroplasty with Cemented Prostheses: A Short-Term, Retrospective, Case-Control Study.

BACKGROUND The present study was performed to determine the potential risk factors for postoperative knee stiffness in patients with anteromedial knee osteoarthritis undergoing unicompartmental knee arthroplasty with cemented prostheses. MATERIAL AND METHODS This retrospective cohort study evaluated patients with anteromedial knee osteoarthritis who underwent medial unicompartmental knee arthroplasty at our hospital between May 2017 and May 2020. The patients were divided into 2 groups according to their prognosis: those who experienced knee stiffness after undergoing unicompartmental knee arthroplasty and those who did not. The factors associated with stiffness after UKA were identified using univariate analysis. Frequencies are used to express categorical variables, while mean±SD is used to express continuous variables. The t test and chi-square test were used. A multivariate logistic regression model was built to identify the risk factors for postoperative stiffness. RESULTS We included 590 knees in the study after unicompartmental knee arthroplasty. The overall incidence of postoperative stiffness in unicompartmental knee arthroplasty surgery was 10.17%. In terms of the radiological measurements, varus deformity (70.34% vs 29.66%) and tibial component posterior slope angle (4.8±2.0 vs 4.6±2.0, P<0.001) were significantly differences between the 2 groups. Four independent risk factors for stiffness after unicompartmental knee arthroplasty were identified: age (95% CI, 1.022-1.048), varus deformity (95% CI, 1.186-1.192), tibial component posterior slope angle (95% CI, 0.550-0.870), and preoperative maximum flexion (95% CI, 0.896-0.923). CONCLUSIONS The overall incidence of postoperative knee stiffness in patients with anteromedial knee osteoarthritis undergoing unicompartmental knee arthroplasty with cemented prostheses was 10.17%, which was at a moderate level compared to patients with other diseases undergoing unicompartmental knee arthroplasty. Four independent risk factors were identified: age, varus deformity, preoperative maximum flexion, and tibial component posterior slope angle. Awareness these risk factors might help surgeons prevent the occurrence of postoperative knee stiffness in patients with UKA.

Improvements in task performance after practice are associated with scale-free dynamics of brain activity.

Although practicing a task generally benefits later performance on that same task, there are individual differences in practice effects. One avenue to model such differences comes from research showing that brain networks extract functional advantages from operating in the vicinity of criticality, a state in which brain network activity is more scale-free. We hypothesized that higher scale-free signal from fMRI data, measured with the Hurst exponent (H), indicates closer proximity to critical states. We tested whether individuals with higher H during repeated task performance would show greater practice effects. In Study 1, participants performed a dual-n-back task (DNB) twice during MRI (n = 56). In Study 2, we used two runs of n-back task (NBK) data from the Human Connectome Project sample (n = 599). In Study 3, participants performed a word completion task (CAST) across six runs (n = 44). In all three studies, multivariate analysis was used to test whether higher H was related to greater practice-related performance improvement. Supporting our hypothesis, we found patterns of higher H that reliably correlated with greater performance improvement across participants in all three studies. However, the predictive brain regions were distinct, suggesting that the specific spatial H↑ patterns are not task-general.

The Cellular Underpinnings of the Human Cortical Connectome.

The functional properties of the human brain arise, in part, from the vast assortment of cell types that pattern the cortex. The cortical sheet can be broadly divided into distinct networks, which are further embedded into processing streams, or gradients, that extend from unimodal systems through higher-order association territories. Here, using transcriptional data from the Allen Human Brain Atlas, we demonstrate that imputed cell type distributions are spatially coupled to the functional organization of cortex, as estimated through fMRI. Cortical cellular profiles follow the macro-scale organization of the functional gradients as well as the associated large-scale networks. Distinct cellular fingerprints were evident across networks, and a classifier trained on post-mortem cell-type distributions was able to predict the functional network allegiance of cortical tissue samples. These data indicate that the in vivo organization of the cortical sheet is reflected in the spatial variability of its cellular composition.

Brain-Based Predictions of Psychiatric Illness-Linked Behaviors Across the Sexes.

BACKGROUND: Individual differences in functional brain connectivity can be used to predict both the presence of psychiatric illness and variability in associated behaviors. However, despite evidence for sex differences in functional network connectivity and in the prevalence, presentation, and trajectory of psychiatric illnesses, the extent to which disorder-relevant aspects of network connectivity are shared or unique across the sexes remains to be determined. METHODS: In this work, we used predictive modeling approaches to evaluate whether shared or unique functional connectivity correlates underlie the expression of psychiatric illness-linked behaviors in males and females in data from the Adolescent Brain Cognitive Development Study (N = 5260; 2571 females). RESULTS: We demonstrate that functional connectivity profiles predict individual differences in externalizing behaviors in males and females but predict internalizing behaviors only in females. Furthermore, models trained to predict externalizing behaviors in males generalize to predict internalizing behaviors in females, and models trained to predict internalizing behaviors in females generalize to predict externalizing behaviors in males. Finally, the neurobiological correlates of many behaviors are largely shared within and across sexes: functional connections within and between heteromodal association networks, including default, limbic, control, and dorsal attention networks, are associated with internalizing and externalizing behaviors. CONCLUSIONS: Taken together, these findings suggest that shared neurobiological patterns may manifest as distinct behaviors across the sexes. Based on these results, we recommend that both clinicians and researchers carefully consider how sex may influence the presentation of psychiatric illnesses, especially those along the internalizing-externalizing spectrum.

Wave-like properties of functional dynamics across the cortical sheet.

The human cortex is organized in a hierarchical manner. Pines et al.1 show that wave-like hemodynamic activity flows along this architecture, from unimodal through association cortices, providing fertile ground for researchers seeking to map links across behavioral and cognitive states.

Differences in the functional brain architecture of sustained attention and working memory in youth and adults.

Sustained attention (SA) and working memory (WM) are critical processes, but the brain networks supporting these abilities in development are unknown. We characterized the functional brain architecture of SA and WM in 9- to 11-year-old children and adults. First, we found that adult network predictors of SA generalized to predict individual differences and fluctuations in SA in youth. A WM model predicted WM performance both across and within children-and captured individual differences in later recognition memory-but underperformed in youth relative to adults. We next characterized functional connections differentially related to SA and WM in youth compared to adults. Results revealed 2 network configurations: a dominant architecture predicting performance in both age groups and a secondary architecture, more prominent for WM than SA, predicting performance in each age group differently. Thus, functional connectivity (FC) predicts SA and WM in youth, with networks predicting WM performance differing more between youths and adults than those predicting SA.

Progress in the total synthesis of resin glycosides.

Resin glycosides, mainly distributed in plants of the family Convolvulaceae, are a class of novel and complex glycolipids. Their structural complexity and significant biological activities have received much attention from synthetic chemists, and a number of interesting resin glycosides have been synthesized. The synthesized resin glycosides and their analogues not only helped in structural verification, structural modification, and further biological activity exploration but also provided enlightenment for the synthesis of glycoside compounds. Herein, the present review summarizes the application of various efforts toward the synthesis of resin glycosides in the last decade.